Florida’s Department of Health announced there’s a “high likelihood” of four locally-transmitted cases of the Zika virus in Miami-Dade and Broward County, the first locally-transmitted cases in the United States, and “believes there’s an active transmission area” that includes Wynwood, Midtown and the Design District areas of Miami.

The department defined the transmission area’s boundaries as U.S. 1 (Biscayne Boulevard) to the east; Northwest Fifth Avenue to the west; 20th Street on the south; and 38th Street on the north.

“While no mosquitoes trapped tested positive for the Zika virus, the department believes these cases were likely transmitted through infected mosquitoes in this area,” the department declared in a news release.

“The department is actively conducting door-to-door outreach and urine sample collection in the impacted area and will share more details as they become available. The results from these efforts will help department determine the number of people affected. These local cases were identified by clinicians who brought them to the attention of the department. In addition, blood banks in the area are currently excluding donations from impacted areas until screening protocols are in place.”